Method and system for master slave protocol communication in an intelligent electronic device

ABSTRACT

A power management architecture for an electrical power distribution system, or portion thereof, is disclosed. The architecture includes intelligent electronic devices (“IED&#39;s”) with the capability to monitor and control attached slave devices, and provide capability to communicate between multiple devices in a variety of communication protocols. A master IED in the master/slave architecture performs power management functions on the data received from the slave IED&#39;s. Further, the IED&#39;s with master functionality provide web server capabilities, allowing a user to view processed data over an open Internet protocol, such as HTTP (“Hyper Text Transfer Protocol”).

RELATED APPLICATIONS

This application is a continuation-in-part under 37 C.F.R. § 1.53(b) ofU.S. patent application Ser. No. 09/723,564, entitled “INTRA-DEVICECOMMUNICATIONS ARCHITECTURE FOR MANAGING ELECTRICAL POWER DISTRIBUTIONAND CONSUMPTION”, filed Nov. 28, 2000, the entire disclosure of which ishereby incorporated by reference. U.S. patent application Ser. No.09/723,564 filed Nov. 28, 2000 is a continuation-in-part under 37 C.F.R.§ 1.53(b) of U.S. patent application Ser. No. 08/798,723 filed Feb. 12,1997, abandoned, which is a continuation-in-part under 37 C.F.R. §1.53(b) of U.S. patent application Ser. No. 08/369,849 filed Dec. 30,1994 now U.S. Pat. No. 5,650,936.

BACKGROUND

The monitoring of electric parameters, such as current, voltage, energy,power, etc., and particularly the measuring and calculating of electricparameters, provides valuable information for power utilities and theircustomers. Monitoring electric power is important to ensure that theelectric power is effectively and efficiently generated, distributed andutilized. Knowledge about power parameters such as volts, amps, watts,phase relationship between waveforms, KWH, KVAR, KVARH, KVA, KVAH, powerfactor, frequency, etc., is a concern for utilities and industrial powerusers. In addition, monitoring electricity can be used for control andprotection purposes.

Many metering functions in a power distribution system requireconcurrent knowledge of the states of multiple circuits or devices inthe system to be communicated to a central command and control entity inorder to work efficiently and effectively. However, a given power systemrarely contains equipment from just one, or even just two,manufacturers. Within the power distribution or monitoring system, thevarious devices are often provided by multiple manufacturers and areconfigured to communicate with multiple different protocols.

Further, current metering devices in use are typically legacy or slavedevices which are difficult to interface with and retrieve data from.These devices often require proprietary or custom software running on acentral server or computer and thus data retrieval can often be complexor costly. In addition, such slave devices, as well as legacy devices,lack the advanced hardware or software, as well as the capability to beupgraded, to communicate in a modern client/server environment andinteract using the open and non-proprietary protocols widely in usetoday.

Accordingly, is it is an object of the present invention to provide asystem that overcomes the disadvantages of the prior art by integratingand consolidating the operations, communications and interactions of anelectrical distribution system comprising a heterogeneous suite ofinter-networked electrical metering devices as well as slave devices andloads, including legacy devices, for the purposes of protection, controland/or metering of electricity.

SUMMARY

The present invention is defined by the following claims, and nothing inthis section should be taken as a limitation on those claims. By way ofintroduction, the preferred embodiments described below relate to anelectrical distribution system architecture of electrical meteringdevices which are interconnected on a network. The metering devicesfurther include capability to monitor and control attached slavedevices, and provide capability to communicate between multiple devicesin a variety of communication protocols.

The energy meter includes one or more sensors which are coupled with anelectric circuit, the sensors operative to sense the electricalparameters in the circuit and generate analog signals which arerepresentative of the electrical parameters. The analog signals areconverted into digital samples using an analog to digital converter anda communications port facilitates communication of the digital signalsto slave devices using a first protocol. The energy meter also includesa server module which allows for communication of the digital samplesonto a digital network using a second protocol. In one embodiment thefirst and second protocols are the same and in an alternate embodimentthe conversion between the first and second protocols is done on aprocessor internal to the energy meter.

According to a further aspect, there is provided a system for monitoringand controlling the distribution of electrical energy in an electriccircuit. The system comprises a communications bus, a digital networkand a master device. The master device comprises one or more sensorswhich are coupled with an electric circuit. The sensors are operative tosense the electrical parameters in the circuit and generate analogsignals which are representative of the electrical parameters. Theanalog signals are converted into digital samples using an analog todigital converter and a communications port facilitates communication ofthe digital signals into a first protocol. The master device alsoincludes a server module which allows for communication of the digitalsamples onto the digital network using a second protocol. The conversionbetween the first and second protocols is done on a processor internalto the master device. According to a further aspect, the system alsoincludes the slave device.

Further aspects and advantages of the invention are discussed below inconjunction with preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a illustrates the block diagram of a Modbus RTU packet;

FIG. 1b illustrates the block diagram of an DNP packet;

FIG. 1c illustrates the block diagram of a the Header frame within a DNPpacket;

FIG. 1d illustrates the block diagram of an ION packet;

FIG. 1e illustrates the block diagram of an Ethernet packet;

FIG. 2 illustrates an IED connected to a network, a slave device and apower system;

FIG. 3 illustrates an block diagram of the preferred embodiment;

FIG. 4a illustrates an IED block diagram of the hardware of thepreferred embodiment;

FIG. 4b illustrates an IED connected to a power system;

FIG. 5 illustrates a master IED coupled with several slave devices and aviewing device attached to one network;

FIG. 6 illustrates a master IED coupled with several slave devices and aviewing device attached to a separate network;

FIG. 7 illustrates a master IED coupled with multiple networks, eachnetwork having it's own protocol;

FIG. 8 illustrates a preferred embodiment with a master IED coupled tomultiple networks, the master IED providing protocol translation orconversion between the networks;

FIG. 9 illustrates a preferred embodiment of a device with bothmaster/slave functionality.

DETAILED DESCRIPTION

Intelligent electronic devices (“IED's”) such as programmable logiccontrollers (“PLC's”), Remote Terminal Units (“RTU's”), electric/watthour meters, protection relays or fault recorders are available thatmake use of memory and microprocessors to provide increased versatilityand additional functionality. Such functionality includes the ability tocommunicate with remote computing systems, either via a directconnection or via a network. In particular, the monitoring of electricalpower, especially the measuring and calculating of electrical/powersystem parameters, provides valuable information for power utilities andtheir customers. The monitoring of electrical power is important toensure that the electrical power is effectively and efficientlygenerated, distributed and utilized. Various different arrangements areavailable for monitoring, measuring, and controlling power systemparameters.

Typically, an IED, such as an individual power measuring device, isplaced on a given branch or line proximate to one or more loads whichare coupled with the branch or line in order to measure, monitor orcontrol power system parameters. Herein, the phrase “coupled with” isdefined to mean directly connected to or indirectly connected throughone or more intermediate components. Such intermediate components mayinclude both hardware and software based components. In addition tomonitoring power parameters of a certain load(s), such power monitoringdevices have a variety of other applications, such as controlapplications. For example, power monitoring devices can be used insupervisory control and data acquisition (“SCADA”) systems such as theXA/21 Energy Management System manufactured by GE Harris Energy ControlSystems located in Melbourne, Fla.

In a typical SCADA application, IED's or other power monitoring devicesindividually dial-in to a central SCADA computer system via a modem.These dial in systems are often “stand alone” and require a secondarydevice, such as a dedicated computer, to send data in a predefined,typically proprietary, protocol. The resulting SCADA data is typicallynot easily/readily accessible by an external user using off the shelfcomputers. The ability to use an open, non-proprietary computer networkinfrastructure, such as the Internet, allows for the use of powerparameter and data transmission and reporting on a large scale utilizingstandard, open and non-proprietary protocols. The Internet provides aconnectionless point-to-point communications medium that is capable ofsupporting standard protocols which are available in virtually everycomputer connected to the Internet.

As used herein, Intelligent electronic devices (“IED's”) includeProgrammable Logic Controllers (“PLC's”), Remote Terminal Units(“RTU's”), electric power meters, protective relays, fault recorders orother devices which are coupled with power distribution networks tomanage and control the distribution and consumption of electrical power.Such devices typically utilize memory and microprocessors executingsoftware to implement one or more desired power management functions.IED's include on-site devices coupled with particular loads or portionsof an electrical distribution system and are used to monitor and managepower generation, distribution and consumption. IED's are also referredherein as power management devices (“PMD's”).

A Remote Terminal Unit (“RTU”) is a field device installed on anelectrical power distribution system at the desired point of metering.It is equipped with input channels (for sensing or metering), outputchannels (for control, indication or alarms) and a communications port.Metered information is typically available through a communicationprotocol via a serial communication port. An exemplary RTU is the XPSeries, manufactured by Quindar Productions Ltd. in Mississauga,Ontario, Canada.

A Programmable Logic Controller (“PLC”) is a solid-state control systemthat has a user-programmable memory for storage of instructions toimplement specific functions such as Input/Output (I/O) control, logic,timing, counting, report generation, communication, arithmetic, and datafile manipulation. A PLC consists of a central processor, I/O interface,and memory. A PLC is designed as an industrial control system. Anexemplary PLC is the SLC 500 Series, manufactured by Allen-Bradley inMilwaukee, Wis.

A meter is a device that records and measures power events, powerquality, current, voltage waveforms, harmonics, transients and otherpower disturbances, in addition to measuring the amount of electricalpower delivered/consumed. Revenue accurate meters (“revenue meters”)relate to revenue accuracy electrical power metering devices with theability to detect, monitor, report, quantify and communicate powerquality information, as well as revenue accurate information, about thepower which they are metering. An exemplary meter is the model 8500meter, manufactured by Power Measurement Ltd, in Saanichton, B.C.Canada.

A protective relay is an electrical device that is designed to interpretinput conditions in a prescribed manner, and after specified conditionsare met, to cause contact operation or similar abrupt change inassociated electric circuits. A relay may consist of several relayunits, each responsive to a specified input, with the combination ofunits providing the desired overall performance characteristics of therelay. Inputs are usually electric but may be mechanical, thermal orotherwise, or a combination thereof. An exemplary relay is the type Nand KC, manufactured by ABB in Raleigh, N.C.

A fault recorder is a device that records the waveform and digitalinputs, such as breaker status which result from a fault in a line, suchas a fault caused by a break in the line. An exemplary fault recorder isthe IDM, manufactured by Hathaway Corp in Littleton, Colo.

IED's can also be created from existing/legacy electromechanical metersor solid-state devices by the addition of a monitoring and controldevice which converts the mechanical output, such as the rotation of therotary counter, or pulse output into electrical pulses/digital data. Anexemplary electromechanical meter is the AB1 Meter manufactured by ABBin Raleigh, N.C. Such conversion devices are known in the art. Herein,legacy refers to devices or platforms inherited from technology earlierthan the current technology.

A system and way are disclosed herein that can bridge the gap betweenmodern and legacy networks and protocols and expand the capability ofthe aforementioned devices and their proprietary communication protocolsand solutions. The disclosed embodiments relate to a communicationsarchitecture that can be used for monitoring, protection and control ofdevices and electrical power distribution in an electrical powerdistribution system, where master IED's interact with other slave IED'sand attached devices, legacy or otherwise, and provide measured orcomputed data over a network. These master IED's, which typically haveIED capabilities as well, offer both a connection between modern andlegacy network protocols as well as server capabilities. Further, servercapabilities include web, HTTP, FTP, NNTP, instant messaging, email andother network based servers. The server capabilities will be describedin detail below. Also described in more detail below is a powermanagement architecture for an electrical power distribution system, orportion thereof. The architecture is also described in the abovecaptioned related application. The architecture provides a medium for amaster device to communicate with several slave or peer devices andprovide data, formatted or otherwise, retrieved therefrom, via alternatereadily accessible formats and protocols.

Further, the architecture allows for a master IED to operate or managethe distribution and consumption of electrical power of devices throughone or more intermediate slave devices. This architecture is createdwith IED's distributed throughout the power distribution system tomonitor and control the flow of electrical power. IED's may bepositioned along the supplier's distribution path and/or within acustomer's internal distribution system. IED's include revenue electricwatt-hour meters, protection relays, programmable logic controllers,remote terminal units, fault recorders and other devices, as describedabove, used to monitor and/or control electrical power distribution,generation, transmission and consumption. As was noted, IED's alsoinclude legacy mechanical or electromechanical devices which have beenretrofitted with appropriate hardware and/or software so as to be ableto integrate with the power management architecture.

Typically, an IED is associated with a particular load or set of loadswhich are drawing electrical power from the power distribution system.As was described above, the IED may also be capable of receiving datafrom or sending as data to its associated load for the purposes ofmonitoring and control. Depending on the type of IED and the type ofload the IED may be associated with, the IED implements/performs one ormore power management functions such as measuring power consumption,controlling power distribution such as a relay function, monitoringpower quality, measuring power parameters such as phasor components,voltage or current, controlling power generation facilities, scalingvalues or combinations thereof. For functions which produce data orother results, the IED can push the data onto the network to anotherIED, central server, or web browser client, automatically or eventdriven, or the IED can wait for a polling communication which requeststhat the data be transmitted to the requestor. A power managementfunction is typically a self-contained function capable of beingperformed or directed by a single IED.

In addition, the IED is also capable of implementing an applicationcomponent of a power management application or module utilizing thearchitecture. As further described below, a power management applicationincludes components which are implemented on different portions of thepower management architecture and communicate with one another via thearchitecture network. The operation of the power management applicationcomponents and their interactions/communications implement the powermanagement application. One or more power management applications may beutilizing the architecture at any given time and therefore, the IED mayimplement one or more power management application components at anygiven time. An exemplary power management application may be a systemwide billing application which collects usage information from multiplelocations throughout the power distribution system and aggregates thetotal usage for the purposes of billing the consumer. In this example,an application component to collect usage from an individual locationand transmit it to a central billing server may be operating on each IEDwhile another application component which collects and aggregates theusage information may be executing on the central billing server. Thecombination of these application components implements the overallbilling application.

The architecture further includes a communications network. Preferably,the communication network is a publicly accessible data network such asthe Internet or other network or combination of sub-networks thattransmit data utilizing the transmission control protocol/Internetprotocol (“TCP/IP”) protocol suite. Such networks include privateintranet networks, virtual private networks, extranets or combinationsthereof and combinations which include the Internet. Alternatively,other communications network architectures may also be used. Each IEDpreferably includes the software and/or hardware necessary to facilitatecommunications over the communications network by the hardware and/orsoftware which implements the power management functions and powermanagement application components.

The hardware and/or software which facilitate network communicationspreferably include a communications protocol stack which provides astandard interface to which the power management functionshardware/software and power management application componentshardware/software interact. As will be discussed in more detail below,in one embodiment, the communications protocol stack is a layeredarchitecture of software components. In the preferred embodiments theselayers or software components include an applications layer, a transportlayer, a routing layer, a switching layer and an interface layer.

The applications layer includes the software which implements powermanagement functions and the power management applications components.Further, the applications layer also includes the communication softwareapplications which support the available methods of networkcommunications. Typically, power management function software interactswith power management hardware to monitor and/or control the portion ofthe power distribution system and/or the load coupled with the IED. Theapplication component further interacts with the power managementfunction software to control the power management function or processdata monitored by the power management function. One or both of thepower management function software and the power management applicationcomponent software interacts with the communication softwareapplications in order to communicate over the network with otherdevices.

The communications software applications include electronic mail clientapplications such as applications which support SMTP, MIME or POPnetwork communications protocols, security client applications such asencryption/decryption or authentication applications such as secure-HTTPor secure sockets layer (“SSL”), or other clients which support standardnetwork communications protocols such as telnet, hypertext transferprotocol (“HTTP”), file transfer protocol (“FTP”), network news transferprotocol (“NNTP”), instant messaging client applications, orcombinations thereof. Other client application protocols includeextensible markup language (“XML”) client protocol and associatedprotocols such as Simple Object Access Protocol (“SOAP”). Further, thecommunications software applications may also include client softwareapplications which support peer to peer or instant messaging basedcommunications. All of the communications software applicationspreferably include the ability to communicate via the security clientsoftware applications to secure the communications transmitted via thenetwork from unauthorized access and to ensure that receivedcommunications are authentic, not compromised and received by theintended recipient. Further, the communications software applicationsinclude the ability for redundant operation through the use of one ormore interface layer components, error detection and correction and theability to communicate through firewalls or similar private networkprotection devices.

The communication software applications further include support formaster protocols, also known as a master/slave protocols, which use amaster device or application to control a network of slave devices. Amaster/slave protocol interaction typically involves the masterinitiating transactions and the slaves responding with the requesteddata or action. Slave devices are both legacy and modern devices whichtypically do not have their own capability to communicate on the powermanagement architecture. However, it can be appreciated that a slavedevice may also be another IED, such as an energy meter, with thecapability to communicate on the power management architecture, butwhich operates in a slave mode. A device with master functionality isutilized to connect with slave devices for several reasons. Masterdevices are utilized for providing a primary operator interface andmanaging overall system functions, collecting and analyzing data andinitiating control actions to slave devices. Many slave devices may belegacy devices which may be only capable of monitoring their equipment,not controlling or performing functions in reaction to the measureddata. Further, device cost, which may include equipment downtime oradded maintenance, may deter an individual from replacing a legacydevice with an alternate device or installing higher-cost master devicesat every location. It therefore may be more feasible, from both a costand functionality point, to control the slave devices or legacy deviceand their associated equipment with a master device. Additionally, amaster device may be utilized to control several slave devices within asystem. For example a user may want to monitor the usage of separatedevices and aggregate the load usage. Connecting the two slave-devicesto a master device can offer this functionality.

Further, master device functionality offers several advantages, such asimproved network response speed, particularly over an Ethernetconnection. The response time to a master device request is typicallyfaster because the master device typically has the data requestedavailable, having already retrieved it from the slave device. Thisreduces the network latency added by having to communicate all the wayto the slave device. This also offers improved network scalability byreducing the load on centralized applications because each master devicebecomes responsible for polling its network of slave devices andproviding the concentrated and/or aggregated data rather than having acentralized application responsible for polling every device on thenetwork. Further, by providing intermediate data concentration and/oraggregation points with the master devices, overall Ethernet networkbandwidth is reduced. The improved network response further offersimproved security because master devices can poll slave devices in aparticular period of time, as well as there are fewer expectedcommunication timeouts in the slave devices with the reduced responsetime. Additionally, functions performed on the master device reducenetwork traffic. Further, master device functionality offers improvedtiming for display of data associated with slave devices. Master deviceswhich offer the ability to make command and control decisions remove thetime delay associated with transport of the data to a secondary orintermediate device. Further, master device functionality removes afailure point in the data logging. Further, the master devicefunctionality allows for improved command and control by allowing themeter to directly control without the need to communicate over Ethernet.

Master protocols include industrial networking protocols such as ModbusRTU or other Modbus protocols such as Modbus Plus, Modbus TCP or ModbusASCII, all developed and available from Modicon Corporation, nowSchneider Electric, located in Andover, Mass. The Modbus protocol is anopen and published protocol that requires a royalty-free license, whichis widely used to establish communication between intelligent devices.Modbus generally defines a message structure that controllers recognizeand use regardless of the type of network they communicate over. TheModbus messaging structure is independent of the physical layer, i.e.network hardware, and is commonly implemented using RS232, RS422 orRS485 serial protocols. Modicon® devices using Modbus RTU cancommunicate with each other and with any other devices over a variety ofnetworks, such as an Ethernet or RS485 network.

The Modbus network, as defined by the protocol, is a single master,multi-drop (more than one device) system that supports up to 247 slavedevices. Other examples of master protocols include Integrated ObjectNetwork (“ION”), Distributed Network Protocol (“DNP”), Lonworks, BACnet,Profibus or IEC 870 standard protocols. These master/slave protocolsenable devices to communicate with each other and with other devicesover a variety of networks. The master/slave protocol can also beapplied in the peer-to-peer architecture where one device requestsinformation from another peer.

All of these protocols define a message structure, i.e. a data formatconsisting of a defined ordering of binary data, and rules forcommunication interaction that controllers recognize and use regardlessof the type of network they communicate over. These protocols are mediaindependent. It will be appreciated by one skilled in the art that amaster protocol can be transmitted over TCP/IP by wrapping/encapsulatingit in the appropriate manner, however a master protocol master can alsocommunicate directly over a particular media without using TCP/IP. Forexample, a ION protocol can be transmitted over a RS232 connectionwithout the additional need for protocol wrapping.

Modbus master devices, also referred to as master devices, are usuallysoftware programs executing on computer workstations, such asDistributed Control Systems (“DCS”). Modbus master devices can also bedevices such as Remote Terminal Units. Modbus slave devices are devicessuch as Programmable Logic Controllers, I/O monitoring devices, relaysand meters. Software programs executing on computer workstations canalso act as slave devices. A Modbus message sent from a master to aslave contains the address of the slave, a command, the requisite dataand an error checksum (cyclic redundancy check (“CRC”)).

Modbus comes in variants, the most common of which are Modbus RTU,Modbus ASCII, Modbus Plus and Modbus/TCP. Modbus RTU (binary) and ModbusASCII are the two basic forms of the Modbus protocol. The ASCII formtransmits each 8 bit byte using two ASCII characters from the ASCIIcharacter set (‘0-9’ and ‘A-F’). The RTU form transmits all bytes inbinary format, i.e. each byte is transmitted as 2 four bit hexadecimalcharacters, making the protocol faster and more efficient. Both formsutilize the serial RS-232/RS-485 protocols as the networking medium.Known limitations of these serial protocols, such as limitedinter-device distances, have reduced the effectiveness of the Modbus RTUand ASCII protocols in modern industrial networking. Modbus Plus is aModicon® proprietary protocol used in industrial networking systems. Ituses token-passing peer-to-peer communications over a proprietarynetworking medium at data transfer rates of one megabit per second(high-speed passing of groups of bits within a layer). Typically thenetwork medium is a shielded twisted-pair cable. The structure ofModbus/TCP is similar to the Modbus RTU packet except that it has anextra six-byte header and does not use the cyclic redundancy check(“CRC”). Modbus/TCP defines the packet structure and connection port forthe industry standard TCP/IP protocol. Modbus/TCP retains the Modbus RTUlimit of 256 bytes to a packet. A protocol variant referred to asEnhanced Modbus/TCP removes this limitation to allow a higher throughputis also utilized.

FIG. 1a illustrates a block diagram of a Modbus RTU Packet. The Modbusdata packet 100 includes an ADDRESS field 104, a FUNCTION code field106, a DATA field 108 and a cyclic redundancy check (“CRC”) field 112.The ADDRESS field 104 contains either two characters (Modbus ASCII) oreight bits (Modbus RTU). An assigned slave device address is in therange of 1-247 decimal. A master addresses a slave by placing the slaveaddress in the field of the message. When a slave responds it places itsown address in the address field to let the master know which slave isresponding.

The FUNCTION code field 106 contains either two characters (ModbusASCII) or eight bits (Modbus RTU). Valid function codes are in the rangeof 1-255 decimal, each code in the range referring to an action theslave is to perform. Conversely, when the slave responds to the master,the function code field is utilized to indicate either a normal or errorresponse. In operation the normal response echo's the original functioncode except that the error response, also referred to as the exceptionresponse, returns a code that is equivalent to the function code withit's most significant bit set to a logic 1.

The DATA field 108 is constructed using a set of two hexadecimal digitsin the range of 00 to FF hex. Depending on the protocol variant, i.e.ASCII or RTU, they can be made from a pair of ASCII characters or fromone RTU character. Typically the data field 108 is 16 bits in length fora RTU character but alternately the data field 108 can be zero length,or non-existent. For example the function code alone may specify theaction and the slave does not require any additional data orinformation.

The Distributed Network Protocol (“DNP”) is an open SCADA protocol whichis used for communications and interoperability among substationcomputers, IED's and Master Stations. Originally developed by Harris,Distributed Automation Products in 1993, ownership has been given to theDNP3 Users Group, a group composed of utilities and vendors who areutilizing the protocol. Harris Distributed Automation is located inMelbourne, Fla. DNP is used for substation automation such as reclosingschemes automation, adaptive relaying, capacitor bank control, auto loadtransfer and bus tie control. DNP is not a general purpose protocol fortransmitting hypertext, multimedia or huge files. DNP Version 3.0, orDNP3, is structured similarly to the Modbus protocol. The basicstructure of a DNP3 packet is shown in FIG. 1b and contains a headerframe 114 and a data frame 118. The header frame 114 structure is shownin FIG. 1c and includes a SYNC field 120, a length field 122, a linkcontrol field 124, a destination address 126, a source address 128 and aerror check sum (“CRC”) 130.

The SYNC frame 120 is two bytes and helps the receivers determine wherethe frame begins. The LENGTH 122 specifies the number of octets in theremainder of the frame, not including the CRC check octets 130. The LINKCONTROL octet 124 is used between sending and receiving link layers tocoordinate their activities. A DESTINATION ADDRESS 126 specifies whichDNP device should process the data and the SOURCE ADDRESS 128 identifieswhich DNP device sent the message. Every DNP device must have a uniqueaddress within the collection of devices sending and receiving messagesto and from one another. As in the Modbus protocol, a CRC check providesa higher degree of assurance that communication errors are detected.

The Integrated Object Network (“ION”) protocol is another open protocoldesigned by Power Measurement Ltd., located in Saanichton, BritishColumbia. The ION packet, as shown in the block diagram in FIG. 1d,contains a CRC field 134, an Application layer 136, a Network layer 138and a Data Link layer 140. For reference, a block diagram of an Ethernetpacket is also shown in FIG. 1e.

Other protocols include the International Electrical Commission 870 part5 (“IEC 870”) protocol standard and the Building Automation and ControlNetwork (“BACnet”) protocol. The IEC 870 protocol supports telecontrolequipment and systems with coded bit serial data transmissions formonitoring and controlling processes. The BACnet protocol is adopted andsupported by the American National Standards Institute (“ANSI”) and theAmerican Society of Heating Refrigeration and Air-Conditioning Engineers(“Ashrae”). BACnet is a non-proprietary open protocol communicationstandard conceived by a consortium of building management, system usersand manufactures.

As described above, the internal software of the IED includes a TCP/IPprotocol stack including the transport layer, routing layer, switchinglayer and the interface layer. The transport layer interfaces theapplications layer to the routing layer and accepts communications fromthe applications layer that are to be transmitted over the network. Thetransport layer breaks up the communications into one or more packets,augments each packet with sequencing and addressing data and hands eachpacket to the routing layer. Similarly, packets which are received fromthe network are reassembled by the transport layer and there-constructed communications are then handed up to the applicationslayer and the appropriate communications application client. Thetransport layer also ensures that all packets which make up a giventransmission are sent or received by the intended destination. Missingor damaged packets are re-requested by the transport layer from thesource of the communication. In the preferred embodiment, the transportlayer implements the transport control protocol (“TCP”).

The routing layer interfaces the transport layer to the switching layer.The routing layer routes each packet received from the transport layerover the network. The routing layer augments each packet with the sourceand destination address information. In the preferred embodiment, therouting layer implements the Internet protocol (“IP”). It will beappreciated that the TCP/IP protocols implement a connectionless packetswitching network which facilitates scalable substantially simultaneouscommunications among multiple devices. The switching layer interfacesthe routing layer to the interface layer. The switching layer andinterface layer are typically integrated. The interface layer comprisesthe actual hardware interface to the network. The interface layer mayinclude an Ethernet interface, a modem, such as a wired modem using theserial line interface protocol (“SLIP”) or point to point protocol(“PPP”), a wired modem which may be an analog or digital modem such as aintegrated services digital network (“ISDN”) modem or digital subscriberline (“DSL”) modem, or a cellular modem. Further, other wirelessinterfaces, such as satellite, Bluetooth or 802.11b compliant devices,may also be used. In addition, AC power line or network power linecarrier data network interface may also be used. Cellular modems furtherprovide the functionality to determine the geographic location of theIED using cellular RF triangulation. Such location information can betransmitted along with other power management data as one factor used Inauthenticating the transmitted data. In the preferred embodiments, theprovided interface layer allows for redundant communicationcapabilities. The interface layer couples the IED with a local areanetwork, such as provided at the customer or utility site.Alternatively, the interface layer can couple the IED with a point ofpresence provided by a local network provider such as an Internetservice provider (“ISP”).

Referring back to the figures, FIG. 2 illustrates a system overview ofthe preferred embodiment while FIG. 3 illustrates a flow diagram of howthe master device makes data available to the client application. FIG. 2shows an exemplary IED 200 having master/slave communicationcapabilities. The IED 200 is coupled with a load/power system 201 forthe purpose of monitoring and/or control. Further, the IED 200 iscoupled with a slave device 235 via a closed/proprietary networkprotocol 209 such as. ION or Modbus RTU. The slave device 235 is furthercoupled with a load for the purpose of monitoring and/or control. TheIED 200 is also coupled with an open/non-proprietary network 207 such asthe Internet for the purpose of communicating with remote devices and/orapplications 220. The IED master/slave device 200 further containsdevice circuitry 210 and a server module 230. The device circuitry 210will be described in detail later. The server module 230 containscommunications capability and web server capability, and interacts withinternal hardware and/or software, such as software applications, in thedevice circuitry 210. It will be appreciated that there may be more thanone server module 230 supporting one or more of the TCP/IP basednetworking protocols described above. The circuitry 210 connects with aslave device 235 over a closed network 209, which communicates using aproprietary or closed master/slave protocol such as ION or Modbus RTU.It will be appreciated that there may be more than one circuitry 210 forconnecting with more than one slave device 235 or the circuitry 210 maybe capable of connecting with more than one slave device 235. The servermodule 230 connects with a client application 220, such as a webbrowser, over an open network 207, which communicates using an opennon-proprietary protocol such as HTTP. It will be appreciated that theserver module 230 may also have the capability to connect with the slavedevice 235, depending on the circuitry 210 configuration.

Referring to FIG. 3, in operation the slave device 235 monitors orcollects data from the load 240. The master/slave device 200 requestsdata from the slave device 235 over the closed protocol network 209(block 300). The slave device collects the data (block 305), such asmonitoring or measurement, etc., and sends the requested data to themaster/slave device 200 over the closed protocol network 209 (block 310)using a first protocol. The data is received by the device circuitry210, which includes a processor (not shown) which is further configuredto process both data from the load/power system 201 and incoming dataform slave devices (block 315). Upon receipt of the data, a function isperformed on the data (block 320). This function may include, forexample, a power management function, and will be explained in detaillater on. The master/slave device 200 then converts the processed datainto an open non-proprietary protocol (block 330), commonly referred toas open protocols to one skilled in the art, such as HTTP. The data isthen passed to the server module 230 where the server makes the new dataavailable (block 340), for viewing, retrieval or transmission. A clientapplication 220, such as a web browser, can then view the data over anopen protocol network 207 from the server module 230 (block 350). Forexample, the server module 230 may receive a request from the clientapplication 220 to view the aggregated usage data from load 201 and load240. The server module 230 receives and processes the request. If thedata is available, the server module 230 serves it to the clientapplication 220 via the network 207. If the data is not available, theserver module 230 passes the request to the device circuitry 210. Thedevice circuitry 210 then requests the current usage data for load 240from the slave device 235 using the closed network 209. The slave devicethen responds with the requested data. The device circuitry 210 alsoobtains the usage data for load 201. The usage data for load 240 and 201is then aggregated and the combined usage data is passed back to theserver module 230 which then serves it to the client application 220.

Referring to FIG. 3, in operation the slave device 235 monitors orcollects data from the load 240. The master/slave device 200 requestsdata from the slave device 235 over the closed protocol network 209(block 300). The slave device collects the data (block 305), such as mymonitoring or measurement, etc., and sends the requested data to themaster/slave device 200 over the closed protocol network 209 (block 310)using a first protocol. The data is received by the device circuitry210, which includes a processor (not shown) which is further configuredto process both data from the load/power system 201 and incoming dataform slave devices (block 315). Upon receipt of the data, a function isperformed on the data (block 320). This function may include, forexample, a power management function, and will be explained in detaillater on. The master/slave device 200 then converts the processed datainto an open non-proprietary protocol (block 330), commonly referred toas open protocols to one skilled in the art, such as HTTP. The data isthen passed to the server module 230 where the server makes the new dataavailable (block 340), for viewing, retrieval or transmission.

A client application 220, such as a web browser, can then view the dataover an open protocol network 207 from the server module 230 (block350). For example, the server module 230 may receive a request from theclient application 220 to view the aggregated usage data from load 201and load 240. The server module 230 receives and processes the request.If the data is available, the server module 230 serves it to the clientapplication 220 via the network 207. If the data is not available, theserver module 230 passes the request to the device circuitry 210. Thedevice circuitry 210 then requests the current usage data for load 240from the slave device 235 using the closed network 209. The slave devicethen responds with the requested data. The device circuitry 210 alsoobtains the usage data for load 201. The usage data for load 240 and 201is then aggregated and the combined usage data is passed back to theserver module 230 which then serves it to the client application 220.

In a second embodiment, a local display client 250 is provided on themaster device 200 and is configured to view the data from the servermodule 230 using an open protocol. The local display client 250 mayinclude a LCD display for display a graphic user interface. For example,the local display client 250 may be configured to operate InternetExplorer™, or a derivative thereof, manufactured by MicrosoftCorporation, located in Redmond Wash., and thus provide the user withlocal viewing of the data associated with the attached slave device 235.

In a third embodiment the server module 230 is further capable ofserving email, FTP file transfers, NNTP, instant messaging and buildingand publishing web pages. Further, a domain name system (“DNS”) addressfor the server is also utilized. Both static and dynamic DNS service canbe utilized by the server module 230.

In a fourth embodiment the Master Device receives data in a firstprotocol (block 310), such as ION protocol, performs a function on thedata (block 320) and converts the new processed data back into the firstprotocol (block 335). As described above the data is then passed to theserver module 230 where the server makes the new data available (block340), for viewing, retrieval or transmission. A client application 220can then view the data over the open protocol network 207 from theserver module 230 (block 350).

FIG. 4b illustrates a third embodiment of an IED 400 for use in a powermanagement or control architecture. It will be appreciated that the IED400 contains the device circuitry 405 as shown in FIG. 4a, but withadditional components, as will be described later. The IED 400 ispreferably coupled with a load 401 via a power distribution system 410,or portion thereof. The IED 400 includes device circuitry 405 and isfurther coupled with a network 407. A device, such as a computer,executing a web/HTML browser program 420, such as Internet Explorer™ isalso attached to the network 407. In the preferred embodiment the webbrowser 420 is located on a computer, such as a personal computer havingat least 32 MB memory and 1 GB hard disk with a Pentium™ or equivalentprocessor or better, executing the Microsoft Windows 98™ operatingsystem and Microsoft Explorer™ or equivalent.

Preferred embodiment algorithms detailed below operate on signal samplesas provided by the DSP 465 and CPU 470. The algorithms may operate onall samples provided or a subset of them. Typically, they operateutilizing 64 samples which represents ½ cycle. It will be appreciatedhowever, that these computations can be performed with a greater orlesser number of samples (with the corresponding buffers adjustedaccordingly), e.g. representing a quarter cycle or eighth of a cycle,down to a single sample. The processing power of the DSP 465 and CPU 470is a limiting factor. The CPU 470, DSP 465, DSP memory 467 form part ofthe device circuitry 405 as is mentioned both earlier and later on.

The CPU 470 is also connected to a user interface 472 which allows usersto program the meter 400 or retrieve revenue or power quality data andgenerally interact with the meter 400. In the preferred embodiment, theuser interface 472 includes a graphical display and a keypad as well asLED, infrared and optical interfaces. It will be appreciated by thoseskilled in the art that the power quality detection and reportingalgorithms detailed herein can be executed by a variety of hardwareconfigurations, all of which are known in the art. It can be appreciatedthat further communications circuitry is coupled with the CPU 470, suchas modem or Ethernet circuitry. An exemplary meter is a type 8500manufactured by Power Measurement Ltd, located in Saanichton, B.C.,Canada.

FIG. 4b illustrates a third embodiment of an IED 400 for use in a powermanagement or control architecture. It will be appreciated that the IED400 contains the device circuitry 405 as shown in FIG. 4a, but withadditional components, as will be described later. The IED 400 ispreferably coupled with a load 401 via a power distribution system 410,or portion thereof. The IED 400 includes device circuitry 405 and isfurther coupled with a network 407. A device, such as a computer,executing a web/HTML browser program 420, such as Internet Explorer™ isalso attached to the network 407. In the preferred embodiment the webbrowser 420 is located on a computer, such as a personal computer havingat least 32 MB memory and 1 GB hard disk with a Pentium™ or equivalentprocessor or better, executing the Microsoft Windows 98™ operatingsystem and Microsoft Explorer™ or equivalent.

The device circuitry 405 includes the internal hardware and software ofthe device, such as the CPU 405 a, memory 405 c, firmware and softwareapplications 405 d, data measurement functions 405 b and communicationsprotocol stack 405 e. The master communication module 406 couples thecomponents of the device circuitry 405 of the IED 400 with thecommunications network 407. Alternate embodiments may have powermanagement control functions 405 b in place of or in addition to datameasurement circuitry. For example, a relay may include a control deviceand corresponding control functions that regulate electricity flow to aload based on preset parameters. Alternatively, a revenue meter mayinclude data measurement circuitry that logs and processes data from aconnected load or other slave devices. IED's may contain one or theother or combinations of such circuitry. In an alternate embodiment thecircuitry includes phasor monitoring circuits (not shown) which comprisephasor transducers that receive analog signals representative ofparameters of electricity in a circuit over the power distributionsystem.

The device circuitry 405 interacts with a master communications module406 which gives the device 400 master device functionality. The mastercommunications module 406 includes software and/or hardware which allowsthe device 400 to communicate using a master protocol to other slavedevices (not shown) attached to the network 407 or a secondary network(not shown). The device circuitry 405 converts the master protocolcommunication to a format which is readable using an open internet basedprotocol, such as HTTP. As described above, the device circuitry 405 isconfigured to process the data contained within the master protocolcommunication format before reconfiguring the data into the secondprotocol. Data processing may include power management functions such asdata aggregation, data scaling, measuring power consumption, controllingpower distribution such as a relay function, monitoring power quality,measuring power parameters such as phasor components, voltage orcurrent, frequency, energy, power, controlling power generationfacilities, or combinations thereof. Other power management commands andfunctions or data processing functions are known to those skilled in theart. An exemplary device that provides such power management functionsis the model 8500 meter, manufactured by Power Measurement Ltd, inSaanichton, B.C. Canada.

Further, the device circuitry 405 is also coupled with a web module 408which performs web server functionality. A web server is a program that,using the client/server model and HTTP, serves files, which includedata, from the web server to a user as web pages. Web servers also allowfunctionality such as serving email, instant messaging, FTP filetransfers and building and publishing web pages. A client/server modeldescribes the relationship between two connecting devices in which oneprogram, the client, makes a request form another program, the server,which fulfills the request. The client/server model provides a way tointerconnect devices and programs that are distributed across differentlocations. The web module's 408 server functionality further facilitatestwo way communications between a non-proprietary client application andthe slave device. In one embodiment the web module 408 allows the device400 to communicate using a non-proprietary protocol over the network407. Referring to FIG. 4 the device 400 acts as the server and the webbrowser 420 acts as the client. The circuitry also allows formanipulation and/or processing of the data received from the slavedevices before communication over the network with the open protocol.The open protocol is a standard communication/application layer protocolsuch as HTTP, SOAP or XML which is compatible with an Ethernet networkprotocol, such as a TCP/IP communications protocol, which is commonlyutilized on a web browser 420. It will be appreciated that other networkinterfaces, such as wireless networks, may be utilized.

FIG. 5 illustrates a device 500, including a master communicationsmodule as described above, with several slave devices 505, 510, 515, allattached to a network 507. In the preferred embodiment a master meter500 is coupled with a network 507, the master meter 500 having thefunctionality to send, receive or communicate with the slave devices505, 510, 515 using a master protocol. It will be appreciated that theslave devices 505, 510, 515 may be connected to corresponding loads orpower systems, for example, load 516 is coupled with slave device 515.As discussed earlier master protocols include protocols such as ModbusMaster, ION, DNP, Lonworks™ or IEC 870 standard protocols. The mastermeter 500 is further coupled with a viewing device 520, such as a webbrowser. The master meter 500 utilizes a server to communicate with theviewing device 520 using a standard viewing protocol, the viewingprotocol different from the master protocol. A user may utilize theviewing device 520 which enables them to view data from a slave device505 through the master meter 500 without requiring the ability of theviewing device 520 to communicate in the master protocol. In oneembodiment the network 507 is an Ethernet network which allows the slavedevices 505, 510, 515, the master meter 500 and the viewing device 520capability to communicate over a singular network.

FIG. 7 illustrates an alternate embodiment where a master device iscoupled with several smaller networks, each network having it's ownprotocol. In this embodiment the communication module on the masterdevice 700 facilitates two way communications between thenon-proprietary client application 740 and the slave device 705 710 715720. For example, the first network 725 communicates between devices 705710 using a Modbus protocol and the second network 730 communicatesbetween devices 715 720 using the ION protocol. The master device 700communication circuitry is coupled with the slave devices 705 710 715720 on either network 725 730, thereby allowing the master device 700 tosend, receive or respond to data or commands sent from the slavedevices. As described earlier the device circuitry converts andprocesses the data or commands from the proprietary protocol such as theModbus protocol or the ION protocol, to a third common Internet networkopen protocol, such as HTTP. The master device's 700 web server allowsthe viewing device 700 to view the data over the network 735. It will beappreciated by one skilled in the art that the data or commandcommunication between slave devices 705 710 715, the master device 735and the viewing device 740 can be bi-directional.

In operation, the master device 600 utilizes two ways of gathering datafrom slave devices. The first is “poll and display” where the masterdevice 600 continuously contacts the slave devices and requests updatesof their measured/sensed data. In operation the meter polls for datafrom the slave devices using the necessary protocol. The slave deviceresponds and provides the requested data. The meter processes thereceived data and converts it to a second, more readily accessibleformat, such as HTML. The data is then made available via the meter'sinternal web server for any HTML client program to access and view.Alternately the master device 600 “polls and stores” data, alsocontinuously contacting the slave devices to request their data and thenprocessing and storing the processed data. Storing the processed data onthe master device 600 for later retrieval reduces the need for themaster device 600 to continuously post the data with its web server andallows the data to be requested or retrieved by a secondary device viathe web server. It will be appreciated that retrieval of the stored datamay be done via the secondary viewing device directly or done via atransmission device, such as an email server.

The second way the master device 600 facilitates the transferring ofdata is when it is activated by the viewing device 620. In operation, auser operates a web browser, such as Microsoft Internet Explorer™, andrequests data from the load 616 which presents data to the slave device615, then to the master device 600. The data transmission is done usinga master protocol and upon receipt by the master device 600, the data isextracted from the transmission. The master device performs a function,described below, on the data and then converts the new data into aprotocol viewable by the web browser, such as HTML. As described earliera function, such as a power monitoring or measurement function, mayinclude data aggregation, measuring power consumption, controlling powerdistribution such as a relay function, monitoring power quality,measuring power parameters such as phasor components, voltage orcurrent, controlling power generation facilities, or other computationsor combinations thereof. It will also be appreciated that controlcommands, such as disconnect the load 616, can be issued from the webbrowser 620 in a protocol or format such as XML or SOAP, which arerouted to the master device 600 and converted into the master protocolin which the slave device 615 communicates. Standard web client softwareis onboard the master device, which is accessible by an Internetconnection.

FIG. 7 illustrates an alternate embodiment where a master device iscoupled with several smaller networks, each network having it's ownprotocol. In this embodiment the communication module on the masterdevice 700 facilitates two way communications between thenon-proprietary client application 740 and the slave device 705, 710,715, 720. For example, the first network 725 communicates betweendevices 705 710 using a Modbus protocol and the second network 730communicates between devices 715, 720 using the ION protocol. The masterdevice 700 communication circuitry is coupled with the slave devices705, 710, 715, 720 on either network 725, 730, thereby allowing themaster device 700 to send, receive or respond to data or commands sentfrom the slave devices. As described earlier the device circuitryconverts and processes the data or commands from the proprietaryprotocol such as the Modbus protocol or the ION protocol, to a thirdcommon Internet network open protocol, such as HTTP. The master device's700 web server allows the viewing device 700 to view the data over thenetwork 735. It will be appreciated by one skilled in the art that thedata or command communication between slave devices 705, 710, 715, themaster device 735 and the viewing device 740 can be bi-directional.

In operation, the master device 700 is configured to “poll and display”data from the first network 725 and its associated slave devices 705,710, continuously requesting the data from the slave devices 705, 710,processing the data and transmitting the data on a third network 735 toa users viewing device such as a web browser 740. The second network730, which communicates data or commands in a different protocol fromthe first network 725, is also connected to the master device 700. Themaster device 700 continuously contacts the slave device 715 on thesecond network 730 requesting data. It will be appreciated that themaster device 700 offers a user the opportunity to access data or sendcommands to all slave devices 705, 710, 715, while three separatenetworks and three separate protocols are utilized.

The master meter 700 is further configured to respond to a slavedevice's data with a power management function. For example, the slavedevice 715 is connected to an associated load 717 and the master device700 continuously requests the measured parameters of the load 717 whichthe slave device 710 is configured to measure. These parameters are, forexample, current, voltage, energy, power, peak power demand, currentdemand, peak current demand, frequency, power factor, per phase power orpower factor, reactive and apparent energy, reactive and apparent poweror power reliability, or combinations thereof. A power managementfunction may involve, for example, a test and response to one of themeasured parameters or processed pieces of data or a general command orcontrol instruction issued to a device. For example the master device700 continuously requests the voltage usage data of the load 717 fromthe slave device. The master device 700 is also configured to employ apower or energy management command or function, such as to indicate analarm to a user and initiate a load shedding command when the measuredvoltage of the load exceeds a predefined level.

Other power management functions include either one or combinations ofalert functions, reporting functions, load control functions, datacollection functions, device management functions, billing or revenuemanagement functions, distributed power management functions,centralized power management functions, power reliability functions,usage or consumption management functions, electrical power generationmanagement functions, device maintenance functions, device frauddetection functions, power outage functions or power quality monitoringor measurement functions. It will be appreciated that these functionscan be initiated or controlled by the master device, the master devicebeing accessible from a viewing device, such as a web browser. In oneembodiment the IED's functionality is controlled using object orientedprogram modules. Object oriented programming, known in the art, allowsusers to manipulate or perform functions or data in relation to eachother. An IED utilizing object oriented programming is described in U.S.Pat. No. 5,650,936.

In an alternate embodiment the master device allows protocol translationor conversion between two systems, as well as their associated devices.For example, as shown in FIG. 8, a master device 800, or meter with aprotocol conversion module (not shown) within the meter circuitry, iscoupled with a relay 805 via the relay network 802. The relay network802 is a serial RS232 connection which communicates using the Modbusprotocol, the master meter 800 continuously requests and receives datafrom the relay 805 using the Modbus protocol. A user may view the relaydata in two locations. First, the master meter's protocol conversionmodule receives the data from the relay 805 in a Modbus protocol andconverts the data into the ION protocol and communicates with the mainsystem viewer 810. In one embodiment the main system viewer 810 is anoperating program, such as ION Enterprise™ or Pegasys™ manufactured byPower Measurement Ltd., which allows the user to both monitor andcontrol both the master meter 800 and all associated loads or connecteddevices. Second, the user may view or control the data via a network 822connection, such as an Ethernet connection, in a browser 825. In oneembodiment the master meter 800 converting the data from the Modbusprotocol into a common Internet protocol such as XML or HTML. The mastermeter 800 also allows a secondary system viewer 850, which communicateswith an alternate protocol, such as BACnet to access the data. In oneembodiment the master meter 800 processes and converts the data in theModbus protocol on the relay network 802 to the alternate BACnetprotocol in the secondary system network 860. The secondary system is,for example, a building air conditioning system which contains airconditioner devices 855. In an alternate embodiment the master meter 800converts the data in the Modbus protocol on the relay network 802 toHTML, thereby allowing the browser 825 to view the data over the network822. The master meter 800 further converts the HTML protocol to theBACnet protocol, thereby allowing the secondary system viewer 850 accessto the data or commands. Thus, the master meter 800 acts as a protocolconversion device between multiple protocols and multiple networks whilemonitoring, measuring and implementing power management functions onconnected devices.

It will also be appreciated that a slave device can also contain masterdevice functionality. A device with master/slave functionality, as shownin FIG. 9, utilizes master functionality to aggregate and process datawithin sub-networks. For example, a master/slave device 955 is connectedto several slave devices 945, 950 on a network 935. Another master/slavedevice 905 is also connected to slave devices 910, 915, 920 withinanother network 930. Both master/slave devices 905, 955 utilize masterfunctionality, as described earlier, polling the data from theassociated slave devices and performing functions, such as aggregationfunctions, on the data. Alternately, when the master device 900 requestsdata from the master/slave devices 905, 945, the master/slave devices905, 945 utilize slave functionality. The master device 600 isconfigured to poll the data from only the master/slave devices 905, 955,thereby reducing the amount of connections and processing power that isrequired by the master device 900.

It is therefore intended that the foregoing detailed description beregarded as illustrative rather than limiting, and that it be understoodthat it is the following claims, including all equivalents, that areintended to define the spirit and scope of this invention.

We claim:
 1. An energy meter for managing the distribution of electricalenergy, said meter comprising: at least one sensor coupled with anelectric circuit and operative to sense at least one electricalparameter in said electric circuit and generate at least one analogsignal indicative thereof; a meter housing; at least one analog todigital converter located in said meter housing and coupled with said atleast one sensor and operative to receive said at least one analogsignal and convert said at least one analog signal to at least one firstdigital signal; a communications port located in said meter housing andoperative to facilitate communications of at least one second digitalsignal between said energy meter and a slave device located outside ofsaid meter housing and coupled with said energy meter using a firstprotocol; a processor located in said meter housing and coupled withsaid at least one analog to digital converter and further coupled withsaid communications port, said processor operative to perform a powermanagement function on said at least one second digital signal andgenerate an output result; and a server module located in said meterhousing and coupled with said processor and operative to facilitatecommunication of said output result to a client application over adigital network located outside of said meter housing using a secondprotocol to manage the distribution of electrical energy.
 2. The energymeter of claim 1 wherein said first protocol comprises a masterprotocol.
 3. The energy meter of claim 2 wherein said master protocolcomprises the Modbus RTU protocol.
 4. The energy meter of claim 2wherein said master protocol comprises distributed networking protocol(“DNP”).
 5. The energy meter of claim 1 wherein said second protocolcomprises a hyper text transfer protocol (“HTTP”) based protocol.
 6. Theenergy meter of claim 5 wherein said HTTP based protocol compriseshypertext markup language (“HTML”).
 7. The energy meter of claim 5wherein said HTTP based protocol comprises extensible markup language(“XML”).
 8. The energy meter of claim 5 wherein said HTTP based protocolcomprises simple mail transport protocol (“SMTP”).
 9. The energy meterof claim 1 wherein said first protocol and said second protocol aresimilar.
 10. The energy meter of claim 1 wherein said digital networkcomprises an Ethernet network.
 11. The energy meter of claim 1 whereinsaid digital network comprises a wireless network.
 12. The energy meterof claim 1 wherein said energy meter comprises at least one objectoriented program module.
 13. The energy meter of claim 1 wherein saidmeter is operative to request first digital data from said slave device,said slave device operative to provide said first digital data uponrequest.
 14. The energy meter of claim 13 wherein said meter is furtheroperative to request second digital data from a second slave devicecoupled with said meter, said second slave device being operative toprovide said second digital data upon request.
 15. The energy meter ofclaim 1 wherein said at least one second digital signal comprisesdigital data generated by said slave device.
 16. A system for managingthe distribution of electrical energy in an electric circuit, saidsystem comprising: (a) a first digital network comprising a firstprotocol; (b) a second digital network comprising a second protocoldifferent from said first protocol; (c) a first slave device coupledwith said first digital network, said first slave device operative tofacilitate communication of digital data onto said first digital networkusing said first protocol; (d) a master device coupled with said firstdigital network and said second digital network and further comprising:(i) at least one sensor coupled with said electric circuit and operativeto sense at least one electrical parameter in said electric circuit andgenerate at least one analog signal indicative thereof; (ii) a meterhousing, wherein said first and second digital networks and said firstslave device are located outside said meter housing; (iii) at least oneanalog to digital converter located in said meter housing and coupledwith said at least one sensor and operative to receive said at least oneanalog signal and convert said at least one analog signal to a digitalsignal representative thereof; (iv) a communications port located insaid meter housing and operative to couple said master device with saidfirst digital network and to facilitate receipt of said digital datafrom said first digital network using said first protocol; (v) aprocessor located in said meter housing and coupled with said analog todigital converter and further coupled with said communications port,said processor operative to perform a power management function on saiddigital data and generate an output result therefrom; (vi) a servermodule located in said meter housing and coupled with said processor andoperative to facilitate communication of said output result over saidsecond digital network using said second protocol to manage thedistribution of electrical energy in said electric circuit.
 17. Thesystem of claim 16 further comprising a second slave device coupled withsaid first digital network and further operative to communicate withsaid master device using said first protocol.
 18. The system of claim 17wherein said master device receives a plurality of said digital datafrom both said first slave device and said second slave device, saidprocessor operative to perform said power management function on saiddigital data and generate said output result.
 19. The system of claim 16wherein said power management function comprises generating an alarmmessage.
 20. The system of claim 16 wherein said power managementfunction comprises generating a load shedding command.
 21. The system ofclaim 16 wherein said power management function comprises generating apower factor control command.
 22. The system of claim 16 wherein saidfirst slave device is an energy meter.
 23. The system of claim 16further wherein said first slave device facilitates communication ofsaid digital data in response to a request from said master device. 24.The system of claim 16 wherein said first slave device is furthercoupled with a load, said slave device operative to at least one ofmonitor and control said load.
 25. A system for managing thedistribution of electrical energy in an electric circuit, said systemcomprising: (a) a first digital network; (b) a master device and a slavedevice each coupled with said first digital network and each furthercomprising: (i) at least one sensor coupled with a portion of saidelectric circuit and operative to sense at least one electricalparameter in said electric circuit and generate at least one analogsignal indicative thereof; (ii) a meter housing, wherein said firstdigital network is located outside of said meter housing, and furtherwherein said master device is located outside of said meter housing ofsaid slave device and said slave device is located outside said meterhousing of said master device; (iii) at least one analog to digitalconverter located in said meter housing and coupled with said at leastone sensor and operative to receive said at least one analog signal andconvert said at least one analog signal to digital data representativethereof; (iv) a communications port located in said meter housing andcoupled with said at least one analog to digital converter and operativeto facilitate communication of said digital data onto said first digitalnetwork; (v) a processor located in said meter housing and coupled withsaid at least one analog to digital converter, said processor operativeto perform a power management function on said digital data and generatean output result; wherein said master device further comprises a servermodule located in said meter housing and coupled with said processor ofsaid master device and operative to facilitate communication of saidoutput result on a second digital network using a first protocol, saidfirst protocol comprising an open protocol, to manage the distributionof electrical energy in said electric circuit.
 26. The system of claim25 wherein said master device comprises a revenue meter.
 27. The systemof claim 25 wherein said master device is operative to communicate witha plurality of slave devices.
 28. The system of claim 25 wherein saidmaster device is operative to communicate with a plurality of slavedevices using an RS232 protocol.
 29. The system of claim 25 wherein saidmaster device is operative to communicate with a plurality of slavedevices using an RS485 protocol.
 30. The system of claim 25 wherein saidslave device facilitates communication using a second protocol, saidsecond protocol different from said first protocol, further wherein saidsecond protocol comprising a closed protocol.
 31. The system of claim 30wherein said closed protocol comprises Modbus RTU protocol.
 32. Thesystem of claim 30 wherein said closed protocol comprises distributednetworking protocol (“DNP”).
 33. The system of claim 25 wherein saidopen protocol comprises a hypertext transport protocol (“HTTP”) basedprotocol.
 34. The system of claim 33 wherein said HTTP based protocolcomprises extensible markup language (“XML”).
 35. The system of claim 33wherein said HTTP based protocol comprises hypertext markup language(“HTML”).
 36. The system of claim 33 wherein said HTTP based protocolcomprises simple mail transport protocol (“SMTP”).
 37. The system ofclaim 25 wherein said master device is operative to export said outputresult to a third device.
 38. The system of claim 37 wherein said thirddevice is operative to perform a power management function on saiddigital data.
 39. The system of claim 38 wherein said power managementfunction comprises an aggregation function.
 40. The system of claim 38wherein said power management function comprises a billing function. 41.The system of claim 38 wherein said power management function comprisesa protection function.
 42. The system of claim 38 wherein said powermanagement function comprises a control function.
 43. The system ofclaim 25 wherein said first digital network is coupled with said seconddigital network.
 44. A method for managing the distribution ofelectrical energy in an electric circuit, said method comprising: (a)Computing a first data value in a slave device located in a firstlocation and coupled with a first network, said first networkimplementing a master protocol; (b) transmitting said first data valueto a master device from said slave device over said first network, saidmaster device located in a second location different from said firstlocation; (c) receiving said first data value by said master device; (d)receiving at least one analog parameter by said master device from apower distribution network coupled with said master device; (e)performing at least one power management function by said master deviceon said first data value and generating a result; and (f) providing saidresult by said master device to a client application coupled with asecond network, said second network implementing an internet protocol,to manage the distribution of electrical energy in said electriccircuit.
 45. The method of claim 44, wherein (a) further comprisesreceiving a command via said first network from said master devicecoupled with said first network.
 46. The method of claim 45, wherein (b)is in response to said command.